• General & History -
• Varieties -
  • Clams
  • Mussels
  • Oysters
• Cleaning and Cooking -
• Health & Nutrition -
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Arc Clams - [Akagai (Japan), Arc Shell, Blood Clam, Blood Cockle, family Arcidae]
Found worldwide, arc clams are generally small. The largest, used for Akagai in sushi bars, are 3 inches max. The photo specimens, purchased frozen in Asian markets, are between 1-1/4 and 1-5/8 inches except the big one (purchased empty) is 2-5/8 inches. Ark clams are unique in having red blood pigments hemoglobin and myoglobin, This gives them better oxygen transfer allowing them to live in murky low oxygen environments. They are sold frozen in Asian markets whole, half shell, or as cooked frozen meat. Details and Cooking.

Cherrystone - see Hard Clam.

Geoduck - [Mirugai (Japan), Giant Clam (U.S. sushi bars), Elephant Trunk Clam (China), King Clam (U.S. marketing), Goiduck, Gweduck, Panopea abrupta]
The Geoduck is the largest burrowing clam in the world. Individuals weighing 15 pounds are recorded and bigger ones rumored but the photo specimen is a normal market size of 2.2 pounds and 12 inches total length (5 inch shell). They are long lived with a record age of 168 years.

This clam is found only on the West Coast of North America from Washington State north through southern Alaska and from the tidal zone to 350 feet deep. The name comes from the Nisqually Indian "gwe-duk" ("dig-deep") and the strange spelling is thought to have been a transcription error.

Geoduck harvesting is tightly controlled both in the U.S. and Canada to assure sustainability. Most of the commercial harvest is sent to Japan and China where it fetches a fine price and that market keeps it expensive here. Some much smaller Panopea species are found off Japan, China and New Zealand. and New Zealand has apparently adopted the geoduck name for theirs. Details and Cooking.

Hard Clam - Quahog - [Quahogs - Chowder Clams, Cherrystones, Topnecks, Littlenecks, Countnecks, Mercenaria mercenaria]
This common North Atlantic is found on the coast of North America from Prince Edward Island, Canada all they way down to the Yucatan Peninsula, Mexico but production is centered along the coast of the state of Rhode Island in New England, USA. Some are now farmed on the US and Mexican Pacific coast, England and northern Europe.

While any size can be called a "quahog" that designation is usually reserved for the largest sizes. The names given above from Chowder Clams to Countnecks are size designations in descending order. The photo specimens are Cherrystones from Mexico and were up to 3.4 inches the long way by 2.7 inches and 1.8 inches thick. 3 pounds yielded just over 6 ounces of meat (12.6%) so at US $2.99/# the meat was $23.73 per pound. The meat is fairly chewy so these are best chopped up. Details and Cooking.

Littleneck - see Hard Clam.

Manila Clam - [Japanese Littleneck, Venerupis philippinarum]
These clams were accidentally introduced in the Pacific Northwest of the U.S. and Canada when Pacific Oysters were brought from Japan. They quickly became an invasive species but are now so popular a harvest both commercially and recreationally that the fishery is highly regulated.

These clams are also an aquaculture crop and are harvested at various sizes from 1-1/4 inch to 2-1/2 inches. The main problem with this crop is slow growth, taking over 3 years to reach harvest size.

The photo specimens were typically 1.9 inches the long way by 1.4 inches and 1 inch thick - 19 clams to the ounce. 32 clams weighed 22.8 ounces and yielded 4 ounces of meat (17.5%). At US $3.99/# the meat was $22.80 per pound. In contrast, frozen "Manilla clam meat" (whole shucked clams) in the Asian markets sells for $2.99 to $3.99 per pound. Details and Cooking.

Quahog - see Hard Clam.

Surf Clam - Atlantic - [Hokkigai (Japan), Skimmer, Hen Clam (Maine), Sea Clam, Giant Clam, Bar Clam (Canada), Spisula solidissima & subspecies]
This very large (often over 6.5 inches) is found in the northwest Atlantic from the southern Gulf of St. Laurence, Canada, to the Gulf of Mexico. It is triangular in shape and lives in sand just to the sea side of the surf zone. In the U.S. the foot (photo - called "tongue") is used to make clam strips and the strap meat around the edge of the shell and the adductor muscle that closes the shell are chopped and used for clam chowder and similar recipes. The foot is also exported to Japan for use as sushi. It is larger than the foot of their local surf clams. Prep & Cooking Details.

Surf Clam - Arctic - [Hokkigai (Japan), Stimpson's Surf Clam, Mactromeris polynyma]
This clam, similar to the Atlantic Surf Clam but a little smaller, is found along the northern coast of North America from Rhode Island all they way around to Southern Alaska and also far offshore in the grand banks. As with the Atlantic Surf Clam the foot, strap meat and adductor muscle are edible, but the main market is Japan for the foot where it is very similar to a locally harvested surf clam. It has not much penetrated the American market due to a color difference with the Atlantic Surf Clam, though experimental aquaculture is under way in the Gulf of Maine See Atlantic Surf Clam for prep & cooking details.

White Clam - [Asian Hard Clam, Meretrix lyrata]
This small clam is a major seafood export for Vietnam, packaged as whole frozen clams or as cooked clam meat. It is easily recognized by the white shell and the dark black streak covering one of the side edges just as though it had been dipped in paint.

The photo specimens are on the large size, at 2 inches wide and 1.2 ounces each. 15-1/8 ounces yielded 1-3/8 ounces of clam meat (9%), or about US $33 per pound. Since you can buy a pound of frozen white clam meat for about $3 per pound, in the shell is clearly a decorator item. Use them when you want picturesque open clams in your soup bowl like in the cookbook photos.

Blue Mussels
Blue Mussel, Mytilus edulis (Atlantic)]
Black Mussel, Mytilus galloprovincalis (Mediterranean)]
Pacific Blue Mussel, Mytilus trossulus (Pacific)]
These three mussels are impossible to tell apart save by molecular genetics. They are cold and temperate water mussels which have been introduced to non-native areas including the Southern Hemisphere. All are widely marketed in the areas where they grow. Younger ones may have radial stripes of various colors but not green.   Photo by Mark A. Wilson contributed to the public domain.

Brown Mussel - [Perna perna]
This South Atlantic mussel is native to the shores of both Africa and South America and has been accidentally introduced to and become a pest along the coast of Texas. It is known for clogging pipes and marine equipment and sinking navigation buoys like it's close relative the Asian Green Mussel. It is a candidate for farming due to is very fast growth but is not yet a commercial crop in the US. In the wild green mussels can be toxic due to dinoflagellates they feed on.

California Mussel - [Mytilus californianus]
These mussels native to the Pacific Coast from the Aleutian Islands to northern Mexico were harvested by the Chumash Indians and their predecessors for about 15,000 years. They have orange flesh and can grow to 8 inches long but are generally a lot smaller. They are still gathered for human consumption and for use as bait but not as a commercial crop. Care must be taken in harvesting and consumption because they can be quite toxic during periods of "red tide".   Photo by Tewy distributed under Creative Commons Attribution 2.5.

Asian Green Mussel - [Philippine Green Mussel, Perna viridis]
This Indo-West Pacific mussel is not yet common in most of the U.S. but is now being farmed in Florida, the Caribbean and South America but is more well known for clogging pipes and marine equipment. It is fast growing and can grow to over 4 inches long. In the wild green mussels can be toxic due to dinoflagellates they feed on and they can concentrate heavy metals in contaminated water.   Photo by U.S. Geological Survey = public domain.

Green Lip Mussel - [New Zealand Green Mussel, Perna canaliculus]
Found only around New Zealand where growing them has become a major industry this is the "Green Mussel" most common in U.S. seafood markets and restaurants. Unlike the other green mussel, P. viridis, it is not suited to tropical climates and can be told from it by radial stripes of brown or red color most visible near the lip.

Atlantic Oyster - [Eastern Oyster, Crassostrea virginica]
The oyster of the U.S. Atlantic coast is much smoother than the Pacific Oyster and not as deep shelled. The shell is elongated and will be marketed at from 2 to 5 inches across the widest point.

Olympia Oyster - [Ostrea lurida]
This is the native Pacific oyster, found from southeast Alaska to Baja but most common in bays and estuaries of the state of Washington. It has a thick irregularly shaped fluted shell which may range from white through purple to black in color and rarely grows larger than 1-1/2 inch across.

Pacific Oyster - [Japanese Oyster, Miyagi Oyster, Kumamoto Oyster, Crassostrea gigas]
Native to the coasts of Japan, Korea and Chine, the Pacific Oysters grown on the U.S. West Coast were brought from Japan in 1912. They are primarily an aquaculture crop but some wild populations now exist in Washington, British Columbia and elsewhere. They have now been distributed worldwide and grow on many non-tropical coasts. Pacific oysters can reach a length of as much as 10 inches but are generally marketed much smaller.

Oysters are a well balanced food containing protein, carbohydrates and lipids and are low in cholesterol. Oysters are an excellent source of vitamins D, C, A, B1(thiamin), B2 (riboflavin), B3 (niacin), iron, copper, iodine, magnesium, calcium, zinc, manganese and phosphorus in good nutritional proportions.